My work at The
Maria Mitchell Observatory during the summer of 1972 was done on stars in VSF
193 in Sagittarius. In this paper I would like to discuss two stars which were
found to have changing periods - one a long period Mira type and the other a
short period RR Lyrae type. The first of these stars temporarily designtated as
B15, (RA 18h 20m 52s, Dec. -28¡ 27:8, 1900, mag. range 12.6-14.5pg), was
discovered at Nantucket during the summer of 1971 by Karen Kwitter. I
re-estimated it on approximately 500 NA plates and about 200 MF and B plates by
comparing its brightness on each plate to standard comparison stars. Next the
magnitude estimates were plotted against Julian day on a scale of 100 days to
the inch, and some pieces of light curves began to be visible.